This invention relates to a device for briding the span or space between two relatively movable sections of a structural floor and consists of two anchoring units and a bridging unit. The bridging unit is articulately connected at each of its outer longitudinal edges with an anchoring unit and is formed by two inter-engaging bridge members. One of the bridge members, which is of male die design, engages by a tongue in a groove of the other bridge member of corresponding female die design, more or less deeply depending on the width state of the joint.